Fuel cells are generally manufactured with electrode layers and a proton conductive layer. The electrode layers used in fuel cells are conventionally produced by applying a catalyst paste that contains carbon supporting a hydrogen reduction catalyst, on carbon paper and heat treating the resultant coating.
However, it has been a problem with those electrode catalyst pastes that the carbon supporting a hydrogen reduction catalyst per se cannot be dispersed uniformly within a water-containing solvent. Mechanical mixing or a similar treatment can produce only a temporary effect, and the paste cannot maintain uniformity until applied on carbon paper so that the resulting electrode layer will be nonuniform.
As such, there has been a demand for a catalyst paste for electrodes production in which the carbon supporting a hydrogen reduction catalyst has been dispersed uniformly and with excellent storage stability.
In consideration of the above circumstances, the present invention has an object of providing a catalyst paste composition for the making of electrodes that has a uniform dispersion condition of carbon supporting a hydrogen reduction catalyst and is excellent in storage stability.